/* * IDE I/O functions * * Basic PIO and command management functionality. * * This code was split off from ide.c. See ide.c for history and original * copyrights. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2, or (at your option) any * later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * For the avoidance of doubt the "preferred form" of this code is one which * is in an open non patent encumbered format. Where cryptographic key signing * forms part of the process of creating an executable the information * including keys needed to generate an equivalently functional executable * are deemed to be part of the source code. */ #include <linux/module.h> #include <linux/types.h> #include <linux/string.h> #include <linux/kernel.h> #include <linux/timer.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <linux/major.h> #include <linux/errno.h> #include <linux/genhd.h> #include <linux/blkpg.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/pci.h> #include <linux/delay.h> #include <linux/ide.h> #include <linux/completion.h> #include <linux/reboot.h> #include <linux/cdrom.h> #include <linux/seq_file.h> #include <linux/device.h> #include <linux/kmod.h> #include <linux/scatterlist.h> #include <linux/bitops.h> #include <asm/byteorder.h> #include <asm/irq.h> #include <asm/uaccess.h> #include <asm/io.h> static int __ide_end_request(ide_drive_t *drive, struct request *rq, int uptodate, unsigned int nr_bytes, int dequeue) { int ret = 1; int error = 0; if (uptodate <= 0) error = uptodate ? uptodate : -EIO; /* * if failfast is set on a request, override number of sectors and * complete the whole request right now */ if (blk_noretry_request(rq) && error) nr_bytes = rq->hard_nr_sectors << 9; if (!blk_fs_request(rq) && error && !rq->errors) rq->errors = -EIO; /* * decide whether to reenable DMA -- 3 is a random magic for now, * if we DMA timeout more than 3 times, just stay in PIO */ if (drive->state == DMA_PIO_RETRY && drive->retry_pio <= 3) { drive->state = 0; ide_dma_on(drive); } if (!__blk_end_request(rq, error, nr_bytes)) { if (dequeue) HWGROUP(drive)->rq = NULL; ret = 0; } return ret; } /** * ide_end_request - complete an IDE I/O * @drive: IDE device for the I/O * @uptodate: * @nr_sectors: number of sectors completed * * This is our end_request wrapper function. We complete the I/O * update random number input and dequeue the request, which if * it was tagged may be out of order. */ int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors) { unsigned int nr_bytes = nr_sectors << 9; struct request *rq; unsigned long flags; int ret = 1; /* * room for locking improvements here, the calls below don't * need the queue lock held at all */ spin_lock_irqsave(&ide_lock, flags); rq = HWGROUP(drive)->rq; if (!nr_bytes) { if (blk_pc_request(rq)) nr_bytes = rq->data_len; else nr_bytes = rq->hard_cur_sectors << 9; } ret = __ide_end_request(drive, rq, uptodate, nr_bytes, 1); spin_unlock_irqrestore(&ide_lock, flags); return ret; } EXPORT_SYMBOL(ide_end_request); /* * Power Management state machine. This one is rather trivial for now, * we should probably add more, like switching back to PIO on suspend * to help some BIOSes, re-do the door locking on resume, etc... */ enum { ide_pm_flush_cache = ide_pm_state_start_suspend, idedisk_pm_standby, idedisk_pm_restore_pio = ide_pm_state_start_resume, idedisk_pm_idle, ide_pm_restore_dma, }; static void ide_complete_power_step(ide_drive_t *drive, struct request *rq, u8 stat, u8 error) { struct request_pm_state *pm = rq->data; if (drive->media != ide_disk) return; switch (pm->pm_step) { case ide_pm_flush_cache: /* Suspend step 1 (flush cache) complete */ if (pm->pm_state == PM_EVENT_FREEZE) pm->pm_step = ide_pm_state_completed; else pm->pm_step = idedisk_pm_standby; break; case idedisk_pm_standby: /* Suspend step 2 (standby) complete */ pm->pm_step = ide_pm_state_completed; break; case idedisk_pm_restore_pio: /* Resume step 1 complete */ pm->pm_step = idedisk_pm_idle; break; case idedisk_pm_idle: /* Resume step 2 (idle) complete */ pm->pm_step = ide_pm_restore_dma; break; } } static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq) { struct request_pm_state *pm = rq->data; ide_task_t *args = rq->special; memset(args, 0, sizeof(*args)); switch (pm->pm_step) { case ide_pm_flush_cache: /* Suspend step 1 (flush cache) */ if (drive->media != ide_disk) break; /* Not supported? Switch to next step now. */ if (!drive->wcache || !ide_id_has_flush_cache(drive->id)) { ide_complete_power_step(drive, rq, 0, 0); return ide_stopped; } if (ide_id_has_flush_cache_ext(drive->id)) args->tf.command = WIN_FLUSH_CACHE_EXT; else args->tf.command = WIN_FLUSH_CACHE; goto out_do_tf; case idedisk_pm_standby: /* Suspend step 2 (standby) */ args->tf.command = WIN_STANDBYNOW1; goto out_do_tf; case idedisk_pm_restore_pio: /* Resume step 1 (restore PIO) */ ide_set_max_pio(drive); /* * skip idedisk_pm_idle for ATAPI devices */ if (drive->media != ide_disk) pm->pm_step = ide_pm_restore_dma; else ide_complete_power_step(drive, rq, 0, 0); return ide_stopped; case idedisk_pm_idle: /* Resume step 2 (idle) */ args->tf.command = WIN_IDLEIMMEDIATE; goto out_do_tf; case ide_pm_restore_dma: /* Resume step 3 (restore DMA) */ /* * Right now, all we do is call ide_set_dma(drive), * we could be smarter and check for current xfer_speed * in struct drive etc... */ if (drive->hwif->dma_host_set == NULL) break; /* * TODO: respect ->using_dma setting */ ide_set_dma(drive); break; } pm->pm_step = ide_pm_state_completed; return ide_stopped; out_do_tf: args->tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE; args->data_phase = TASKFILE_NO_DATA; return do_rw_taskfile(drive, args); } /** * ide_end_dequeued_request - complete an IDE I/O * @drive: IDE device for the I/O * @uptodate: * @nr_sectors: number of sectors completed * * Complete an I/O that is no longer on the request queue. This * typically occurs when we pull the request and issue a REQUEST_SENSE. * We must still finish the old request but we must not tamper with the * queue in the meantime. * * NOTE: This path does not handle barrier, but barrier is not supported * on ide-cd anyway. */ int ide_end_dequeued_request(ide_drive_t *drive, struct request *rq, int uptodate, int nr_sectors) { unsigned long flags; int ret; spin_lock_irqsave(&ide_lock, flags); BUG_ON(!blk_rq_started(rq)); ret = __ide_end_request(drive, rq, uptodate, nr_sectors << 9, 0); spin_unlock_irqrestore(&ide_lock, flags); return ret; } EXPORT_SYMBOL_GPL(ide_end_dequeued_request); /** * ide_complete_pm_request - end the current Power Management request * @drive: target drive * @rq: request * * This function cleans up the current PM request and stops the queue * if necessary. */ static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq) { unsigned long flags; #ifdef DEBUG_PM printk("%s: completing PM request, %s\n", drive->name, blk_pm_suspend_request(rq) ? "suspend" : "resume"); #endif spin_lock_irqsave(&ide_lock, flags); if (blk_pm_suspend_request(rq)) { blk_stop_queue(drive->queue); } else { drive->blocked = 0; blk_start_queue(drive->queue); } HWGROUP(drive)->rq = NULL; if (__blk_end_request(rq, 0, 0)) BUG(); spin_unlock_irqrestore(&ide_lock, flags); } void ide_tf_read(ide_drive_t *drive, ide_task_t *task) { ide_hwif_t *hwif = drive->hwif; struct ide_taskfile *tf = &task->tf; if (task->tf_flags & IDE_TFLAG_IN_DATA) { u16 data = hwif->INW(IDE_DATA_REG); tf->data = data & 0xff; tf->hob_data = (data >> 8) & 0xff; } /* be sure we're looking at the low order bits */ hwif->OUTB(drive->ctl & ~0x80, IDE_CONTROL_REG); if (task->tf_flags & IDE_TFLAG_IN_NSECT) tf->nsect = hwif->INB(IDE_NSECTOR_REG); if (task->tf_flags & IDE_TFLAG_IN_LBAL) tf->lbal = hwif->INB(IDE_SECTOR_REG); if (task->tf_flags & IDE_TFLAG_IN_LBAM) tf->lbam = hwif->INB(IDE_LCYL_REG); if (task->tf_flags & IDE_TFLAG_IN_LBAH) tf->lbah = hwif->INB(IDE_HCYL_REG); if (task->tf_flags & IDE_TFLAG_IN_DEVICE) tf->device = hwif->INB(IDE_SELECT_REG); if (task->tf_flags & IDE_TFLAG_LBA48) { hwif->OUTB(drive->ctl | 0x80, IDE_CONTROL_REG); if (task->tf_flags & IDE_TFLAG_IN_HOB_FEATURE) tf->hob_feature = hwif->INB(IDE_FEATURE_REG); if (task->tf_flags & IDE_TFLAG_IN_HOB_NSECT) tf->hob_nsect = hwif->INB(IDE_NSECTOR_REG); if (task->tf_flags & IDE_TFLAG_IN_HOB_LBAL) tf->hob_lbal = hwif->INB(IDE_SECTOR_REG); if (task->tf_flags & IDE_TFLAG_IN_HOB_LBAM) tf->hob_lbam = hwif->INB(IDE_LCYL_REG); if (task->tf_flags & IDE_TFLAG_IN_HOB_LBAH) tf->hob_lbah = hwif->INB(IDE_HCYL_REG); } } /** * ide_end_drive_cmd - end an explicit drive command * @drive: command * @stat: status bits * @err: error bits * * Clean up after success/failure of an explicit drive command. * These get thrown onto the queue so they are synchronized with * real I/O operations on the drive. * * In LBA48 mode we have to read the register set twice to get * all the extra information out. */ void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err) { unsigned long flags; struct request *rq; spin_lock_irqsave(&ide_lock, flags); rq = HWGROUP(drive)->rq; spin_unlock_irqrestore(&ide_lock, flags); if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) { ide_task_t *args = (ide_task_t *) rq->special; if (rq->errors == 0) rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT); if (args) { struct ide_taskfile *tf = &args->tf; tf->error = err; tf->status = stat; ide_tf_read(drive, args); } } else if (blk_pm_request(rq)) { struct request_pm_state *pm = rq->data; #ifdef DEBUG_PM printk("%s: complete_power_step(step: %d, stat: %x, err: %x)\n", drive->name, rq->pm->pm_step, stat, err); #endif ide_complete_power_step(drive, rq, stat, err); if (pm->pm_step == ide_pm_state_completed) ide_complete_pm_request(drive, rq); return; } spin_lock_irqsave(&ide_lock, flags); HWGROUP(drive)->rq = NULL; rq->errors = err; if (__blk_end_request(rq, (rq->errors ? -EIO : 0), 0)) BUG(); spin_unlock_irqrestore(&ide_lock, flags); } EXPORT_SYMBOL(ide_end_drive_cmd); /** * try_to_flush_leftover_data - flush junk * @drive: drive to flush * * try_to_flush_leftover_data() is invoked in response to a drive * unexpectedly having its DRQ_STAT bit set. As an alternative to * resetting the drive, this routine tries to clear the condition * by read a sector's worth of data from the drive. Of course, * this may not help if the drive is *waiting* for data from *us*. */ static void try_to_flush_leftover_data (ide_drive_t *drive) { int i = (drive->mult_count ? drive->mult_count : 1) * SECTOR_WORDS; if (drive->media != ide_disk) return; while (i > 0) { u32 buffer[16]; u32 wcount = (i > 16) ? 16 : i; i -= wcount; HWIF(drive)->ata_input_data(drive, buffer, wcount); } } static void ide_kill_rq(ide_drive_t *drive, struct request *rq) { if (rq->rq_disk) { ide_driver_t *drv; drv = *(ide_driver_t **)rq->rq_disk->private_data; drv->end_request(drive, 0, 0); } else ide_end_request(drive, 0, 0); } static ide_startstop_t ide_ata_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err) { ide_hwif_t *hwif = drive->hwif; if (stat & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) { /* other bits are useless when BUSY */ rq->errors |= ERROR_RESET; } else if (stat & ERR_STAT) { /* err has different meaning on cdrom and tape */ if (err == ABRT_ERR) { if (drive->select.b.lba && /* some newer drives don't support WIN_SPECIFY */ hwif->INB(IDE_COMMAND_REG) == WIN_SPECIFY) return ide_stopped; } else if ((err & BAD_CRC) == BAD_CRC) { /* UDMA crc error, just retry the operation */ drive->crc_count++; } else if (err & (BBD_ERR | ECC_ERR)) { /* retries won't help these */ rq->errors = ERROR_MAX; } else if (err & TRK0_ERR) { /* help it find track zero */ rq->errors |= ERROR_RECAL; } } if ((stat & DRQ_STAT) && rq_data_dir(rq) == READ && (hwif->host_flags & IDE_HFLAG_ERROR_STOPS_FIFO) == 0) try_to_flush_leftover_data(drive); if (rq->errors >= ERROR_MAX || blk_noretry_request(rq)) { ide_kill_rq(drive, rq); return ide_stopped; } if (ide_read_status(drive) & (BUSY_STAT | DRQ_STAT)) rq->errors |= ERROR_RESET; if ((rq->errors & ERROR_RESET) == ERROR_RESET) { ++rq->errors; return ide_do_reset(drive); } if ((rq->errors & ERROR_RECAL) == ERROR_RECAL) drive->special.b.recalibrate = 1; ++rq->errors; return ide_stopped; } static ide_startstop_t ide_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err) { ide_hwif_t *hwif = drive->hwif; if (stat & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) { /* other bits are useless when BUSY */ rq->errors |= ERROR_RESET; } else { /* add decoding error stuff */ } if (ide_read_status(drive) & (BUSY_STAT | DRQ_STAT)) /* force an abort */ hwif->OUTB(WIN_IDLEIMMEDIATE, IDE_COMMAND_REG); if (rq->errors >= ERROR_MAX) { ide_kill_rq(drive, rq); } else { if ((rq->errors & ERROR_RESET) == ERROR_RESET) { ++rq->errors; return ide_do_reset(drive); } ++rq->errors; } return ide_stopped; } ide_startstop_t __ide_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err) { if (drive->media == ide_disk) return ide_ata_error(drive, rq, stat, err); return ide_atapi_error(drive, rq, stat, err); } EXPORT_SYMBOL_GPL(__ide_error); /** * ide_error - handle an error on the IDE * @drive: drive the error occurred on * @msg: message to report * @stat: status bits * * ide_error() takes action based on the error returned by the drive. * For normal I/O that may well include retries. We deal with * both new-style (taskfile) and old style command handling here. * In the case of taskfile command handling there is work left to * do */ ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat) { struct request *rq; u8 err; err = ide_dump_status(drive, msg, stat); if ((rq = HWGROUP(drive)->rq) == NULL) return ide_stopped; /* retry only "normal" I/O: */ if (!blk_fs_request(rq)) { rq->errors = 1; ide_end_drive_cmd(drive, stat, err); return ide_stopped; } if (rq->rq_disk) { ide_driver_t *drv; drv = *(ide_driver_t **)rq->rq_disk->private_data; return drv->error(drive, rq, stat, err); } else return __ide_error(drive, rq, stat, err); } EXPORT_SYMBOL_GPL(ide_error); ide_startstop_t __ide_abort(ide_drive_t *drive, struct request *rq) { if (drive->media != ide_disk) rq->errors |= ERROR_RESET; ide_kill_rq(drive, rq); return ide_stopped; } EXPORT_SYMBOL_GPL(__ide_abort); /** * ide_abort - abort pending IDE operations * @drive: drive the error occurred on * @msg: message to report * * ide_abort kills and cleans up when we are about to do a * host initiated reset on active commands. Longer term we * want handlers to have sensible abort handling themselves * * This differs fundamentally from ide_error because in * this case the command is doing just fine when we * blow it away. */ ide_startstop_t ide_abort(ide_drive_t *drive, const char *msg) { struct request *rq; if (drive == NULL || (rq = HWGROUP(drive)->rq) == NULL) return ide_stopped; /* retry only "normal" I/O: */ if (!blk_fs_request(rq)) { rq->errors = 1; ide_end_drive_cmd(drive, BUSY_STAT, 0); return ide_stopped; } if (rq->rq_disk) { ide_driver_t *drv; drv = *(ide_driver_t **)rq->rq_disk->private_data; return drv->abort(drive, rq); } else return __ide_abort(drive, rq); } static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf) { tf->nsect = drive->sect; tf->lbal = drive->sect; tf->lbam = drive->cyl; tf->lbah = drive->cyl >> 8; tf->device = ((drive->head - 1) | drive->select.all) & ~ATA_LBA; tf->command = WIN_SPECIFY; } static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf) { tf->nsect = drive->sect; tf->command = WIN_RESTORE; } static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf) { tf->nsect = drive->mult_req; tf->command = WIN_SETMULT; } static ide_startstop_t ide_disk_special(ide_drive_t *drive) { special_t *s = &drive->special; ide_task_t args; memset(&args, 0, sizeof(ide_task_t)); args.data_phase = TASKFILE_NO_DATA; if (s->b.set_geometry) { s->b.set_geometry = 0; ide_tf_set_specify_cmd(drive, &args.tf); } else if (s->b.recalibrate) { s->b.recalibrate = 0; ide_tf_set_restore_cmd(drive, &args.tf); } else if (s->b.set_multmode) { s->b.set_multmode = 0; if (drive->mult_req > drive->id->max_multsect) drive->mult_req = drive->id->max_multsect; ide_tf_set_setmult_cmd(drive, &args.tf); } else if (s->all) { int special = s->all; s->all = 0; printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special); return ide_stopped; } args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE | IDE_TFLAG_CUSTOM_HANDLER; do_rw_taskfile(drive, &args); return ide_started; } /* * handle HDIO_SET_PIO_MODE ioctl abusers here, eventually it will go away */ static int set_pio_mode_abuse(ide_hwif_t *hwif, u8 req_pio) { switch (req_pio) { case 202: case 201: case 200: case 102: case 101: case 100: return (hwif->host_flags & IDE_HFLAG_ABUSE_DMA_MODES) ? 1 : 0; case 9: case 8: return (hwif->host_flags & IDE_HFLAG_ABUSE_PREFETCH) ? 1 : 0; case 7: case 6: return (hwif->host_flags & IDE_HFLAG_ABUSE_FAST_DEVSEL) ? 1 : 0; default: return 0; } } /** * do_special - issue some special commands * @drive: drive the command is for * * do_special() is used to issue WIN_SPECIFY, WIN_RESTORE, and WIN_SETMULT * commands to a drive. It used to do much more, but has been scaled * back. */ static ide_startstop_t do_special (ide_drive_t *drive) { special_t *s = &drive->special; #ifdef DEBUG printk("%s: do_special: 0x%02x\n", drive->name, s->all); #endif if (s->b.set_tune) { ide_hwif_t *hwif = drive->hwif; u8 req_pio = drive->tune_req; s->b.set_tune = 0; if (set_pio_mode_abuse(drive->hwif, req_pio)) { if (hwif->set_pio_mode == NULL) return ide_stopped; /* * take ide_lock for drive->[no_]unmask/[no_]io_32bit */ if (req_pio == 8 || req_pio == 9) { unsigned long flags; spin_lock_irqsave(&ide_lock, flags); hwif->set_pio_mode(drive, req_pio); spin_unlock_irqrestore(&ide_lock, flags); } else hwif->set_pio_mode(drive, req_pio); } else { int keep_dma = drive->using_dma; ide_set_pio(drive, req_pio); if (hwif->host_flags & IDE_HFLAG_SET_PIO_MODE_KEEP_DMA) { if (keep_dma) ide_dma_on(drive); } } return ide_stopped; } else { if (drive->media == ide_disk) return ide_disk_special(drive); s->all = 0; drive->mult_req = 0; return ide_stopped; } } void ide_map_sg(ide_drive_t *drive, struct request *rq) { ide_hwif_t *hwif = drive->hwif; struct scatterlist *sg = hwif->sg_table; if (hwif->sg_mapped) /* needed by ide-scsi */ return; if (rq->cmd_type != REQ_TYPE_ATA_TASKFILE) { hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg); } else { sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE); hwif->sg_nents = 1; } } EXPORT_SYMBOL_GPL(ide_map_sg); void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq) { ide_hwif_t *hwif = drive->hwif; hwif->nsect = hwif->nleft = rq->nr_sectors; hwif->cursg_ofs = 0; hwif->cursg = NULL; } EXPORT_SYMBOL_GPL(ide_init_sg_cmd); /** * execute_drive_command - issue special drive command * @drive: the drive to issue the command on * @rq: the request structure holding the command * * execute_drive_cmd() issues a special drive command, usually * initiated by ioctl() from the external hdparm program. The * command can be a drive command, drive task or taskfile * operation. Weirdly you can call it with NULL to wait for * all commands to finish. Don't do this as that is due to change */ static ide_startstop_t execute_drive_cmd (ide_drive_t *drive, struct request *rq) { ide_hwif_t *hwif = HWIF(drive); ide_task_t *task = rq->special; if (task) { hwif->data_phase = task->data_phase; switch (hwif->data_phase) { case TASKFILE_MULTI_OUT: case TASKFILE_OUT: case TASKFILE_MULTI_IN: case TASKFILE_IN: ide_init_sg_cmd(drive, rq); ide_map_sg(drive, rq); default: break; } return do_rw_taskfile(drive, task); } /* * NULL is actually a valid way of waiting for * all current requests to be flushed from the queue. */ #ifdef DEBUG printk("%s: DRIVE_CMD (null)\n", drive->name); #endif ide_end_drive_cmd(drive, ide_read_status(drive), ide_read_error(drive)); return ide_stopped; } static void ide_check_pm_state(ide_drive_t *drive, struct request *rq) { struct request_pm_state *pm = rq->data; if (blk_pm_suspend_request(rq) && pm->pm_step == ide_pm_state_start_suspend) /* Mark drive blocked when starting the suspend sequence. */ drive->blocked = 1; else if (blk_pm_resume_request(rq) && pm->pm_step == ide_pm_state_start_resume) { /* * The first thing we do on wakeup is to wait for BSY bit to * go away (with a looong timeout) as a drive on this hwif may * just be POSTing itself. * We do that before even selecting as the "other" device on * the bus may be broken enough to walk on our toes at this * point. */ int rc; #ifdef DEBUG_PM printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name); #endif rc = ide_wait_not_busy(HWIF(drive), 35000); if (rc) printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name); SELECT_DRIVE(drive); ide_set_irq(drive, 1); rc = ide_wait_not_busy(HWIF(drive), 100000); if (rc) printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name); } } /** * start_request - start of I/O and command issuing for IDE * * start_request() initiates handling of a new I/O request. It * accepts commands and I/O (read/write) requests. It also does * the final remapping for weird stuff like EZDrive. Once * device mapper can work sector level the EZDrive stuff can go away * * FIXME: this function needs a rename */ static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq) { ide_startstop_t startstop; sector_t block; BUG_ON(!blk_rq_started(rq)); #ifdef DEBUG printk("%s: start_request: current=0x%08lx\n", HWIF(drive)->name, (unsigned long) rq); #endif /* bail early if we've exceeded max_failures */ if (drive->max_failures && (drive->failures > drive->max_failures)) { rq->cmd_flags |= REQ_FAILED; goto kill_rq; } block = rq->sector; if (blk_fs_request(rq) && (drive->media == ide_disk || drive->media == ide_floppy)) { block += drive->sect0; } /* Yecch - this will shift the entire interval, possibly killing some innocent following sector */ if (block == 0 && drive->remap_0_to_1 == 1) block = 1; /* redirect MBR access to EZ-Drive partn table */ if (blk_pm_request(rq)) ide_check_pm_state(drive, rq); SELECT_DRIVE(drive); if (ide_wait_stat(&startstop, drive, drive->ready_stat, BUSY_STAT|DRQ_STAT, WAIT_READY)) { printk(KERN_ERR "%s: drive not ready for command\n", drive->name); return startstop; } if (!drive->special.all) { ide_driver_t *drv; /* * We reset the drive so we need to issue a SETFEATURES. * Do it _after_ do_special() restored device parameters. */ if (drive->current_speed == 0xff) ide_config_drive_speed(drive, drive->desired_speed); if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) return execute_drive_cmd(drive, rq); else if (blk_pm_request(rq)) { struct request_pm_state *pm = rq->data; #ifdef DEBUG_PM printk("%s: start_power_step(step: %d)\n", drive->name, rq->pm->pm_step); #endif startstop = ide_start_power_step(drive, rq); if (startstop == ide_stopped && pm->pm_step == ide_pm_state_completed) ide_complete_pm_request(drive, rq); return startstop; } drv = *(ide_driver_t **)rq->rq_disk->private_data; return drv->do_request(drive, rq, block); } return do_special(drive); kill_rq: ide_kill_rq(drive, rq); return ide_stopped; } /** * ide_stall_queue - pause an IDE device * @drive: drive to stall * @timeout: time to stall for (jiffies) * * ide_stall_queue() can be used by a drive to give excess bandwidth back * to the hwgroup by sleeping for timeout jiffies. */ void ide_stall_queue (ide_drive_t *drive, unsigned long timeout) { if (timeout > WAIT_WORSTCASE) timeout = WAIT_WORSTCASE; drive->sleep = timeout + jiffies; drive->sleeping = 1; } EXPORT_SYMBOL(ide_stall_queue); #define WAKEUP(drive) ((drive)->service_start + 2 * (drive)->service_time) /** * choose_drive - select a drive to service * @hwgroup: hardware group to select on * * choose_drive() selects the next drive which will be serviced. * This is necessary because the IDE layer can't issue commands * to both drives on the same cable, unlike SCSI. */ static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup) { ide_drive_t *drive, *best; repeat: best = NULL; drive = hwgroup->drive; /* * drive is doing pre-flush, ordered write, post-flush sequence. even * though that is 3 requests, it must be seen as a single transaction. * we must not preempt this drive until that is complete */ if (blk_queue_flushing(drive->queue)) { /* * small race where queue could get replugged during * the 3-request flush cycle, just yank the plug since * we want it to finish asap */ blk_remove_plug(drive->queue); return drive; } do { if ((!drive->sleeping || time_after_eq(jiffies, drive->sleep)) && !elv_queue_empty(drive->queue)) { if (!best || (drive->sleeping && (!best->sleeping || time_before(drive->sleep, best->sleep))) || (!best->sleeping && time_before(WAKEUP(drive), WAKEUP(best)))) { if (!blk_queue_plugged(drive->queue)) best = drive; } } } while ((drive = drive->next) != hwgroup->drive); if (best && best->nice1 && !best->sleeping && best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) { long t = (signed long)(WAKEUP(best) - jiffies); if (t >= WAIT_MIN_SLEEP) { /* * We *may* have some time to spare, but first let's see if * someone can potentially benefit from our nice mood today.. */ drive = best->next; do { if (!drive->sleeping && time_before(jiffies - best->service_time, WAKEUP(drive)) && time_before(WAKEUP(drive), jiffies + t)) { ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP)); goto repeat; } } while ((drive = drive->next) != best); } } return best; } /* * Issue a new request to a drive from hwgroup * Caller must have already done spin_lock_irqsave(&ide_lock, ..); * * A hwgroup is a serialized group of IDE interfaces. Usually there is * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640) * may have both interfaces in a single hwgroup to "serialize" access. * Or possibly multiple ISA interfaces can share a common IRQ by being grouped * together into one hwgroup for serialized access. * * Note also that several hwgroups can end up sharing a single IRQ, * possibly along with many other devices. This is especially common in * PCI-based systems with off-board IDE controller cards. * * The IDE driver uses the single global ide_lock spinlock to protect * access to the request queues, and to protect the hwgroup->busy flag. * * The first thread into the driver for a particular hwgroup sets the * hwgroup->busy flag to indicate that this hwgroup is now active, * and then initiates processing of the top request from the request queue. * * Other threads attempting entry notice the busy setting, and will simply * queue their new requests and exit immediately. Note that hwgroup->busy * remains set even when the driver is merely awaiting the next interrupt. * Thus, the meaning is "this hwgroup is busy processing a request". * * When processing of a request completes, the completing thread or IRQ-handler * will start the next request from the queue. If no more work remains, * the driver will clear the hwgroup->busy flag and exit. * * The ide_lock (spinlock) is used to protect all access to the * hwgroup->busy flag, but is otherwise not needed for most processing in * the driver. This makes the driver much more friendlier to shared IRQs * than previous designs, while remaining 100% (?) SMP safe and capable. */ static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq) { ide_drive_t *drive; ide_hwif_t *hwif; struct request *rq; ide_startstop_t startstop; int loops = 0; /* for atari only: POSSIBLY BROKEN HERE(?) */ ide_get_lock(ide_intr, hwgroup); /* caller must own ide_lock */ BUG_ON(!irqs_disabled()); while (!hwgroup->busy) { hwgroup->busy = 1; drive = choose_drive(hwgroup); if (drive == NULL) { int sleeping = 0; unsigned long sleep = 0; /* shut up, gcc */ hwgroup->rq = NULL; drive = hwgroup->drive; do { if (drive->sleeping && (!sleeping || time_before(drive->sleep, sleep))) { sleeping = 1; sleep = drive->sleep; } } while ((drive = drive->next) != hwgroup->drive); if (sleeping) { /* * Take a short snooze, and then wake up this hwgroup again. * This gives other hwgroups on the same a chance to * play fairly with us, just in case there are big differences * in relative throughputs.. don't want to hog the cpu too much. */ if (time_before(sleep, jiffies + WAIT_MIN_SLEEP)) sleep = jiffies + WAIT_MIN_SLEEP; #if 1 if (timer_pending(&hwgroup->timer)) printk(KERN_CRIT "ide_set_handler: timer already active\n"); #endif /* so that ide_timer_expiry knows what to do */ hwgroup->sleeping = 1; hwgroup->req_gen_timer = hwgroup->req_gen; mod_timer(&hwgroup->timer, sleep); /* we purposely leave hwgroup->busy==1 * while sleeping */ } else { /* Ugly, but how can we sleep for the lock * otherwise? perhaps from tq_disk? */ /* for atari only */ ide_release_lock(); hwgroup->busy = 0; } /* no more work for this hwgroup (for now) */ return; } again: hwif = HWIF(drive); if (hwgroup->hwif->sharing_irq && hwif != hwgroup->hwif) { /* * set nIEN for previous hwif, drives in the * quirk_list may not like intr setups/cleanups */ if (drive->quirk_list != 1) ide_set_irq(drive, 0); } hwgroup->hwif = hwif; hwgroup->drive = drive; drive->sleeping = 0; drive->service_start = jiffies; if (blk_queue_plugged(drive->queue)) { printk(KERN_ERR "ide: huh? queue was plugged!\n"); break; } /* * we know that the queue isn't empty, but this can happen * if the q->prep_rq_fn() decides to kill a request */ rq = elv_next_request(drive->queue); if (!rq) { hwgroup->busy = 0; break; } /* * Sanity: don't accept a request that isn't a PM request * if we are currently power managed. This is very important as * blk_stop_queue() doesn't prevent the elv_next_request() * above to return us whatever is in the queue. Since we call * ide_do_request() ourselves, we end up taking requests while * the queue is blocked... * * We let requests forced at head of queue with ide-preempt * though. I hope that doesn't happen too much, hopefully not * unless the subdriver triggers such a thing in its own PM * state machine. * * We count how many times we loop here to make sure we service * all drives in the hwgroup without looping for ever */ if (drive->blocked && !blk_pm_request(rq) && !(rq->cmd_flags & REQ_PREEMPT)) { drive = drive->next ? drive->next : hwgroup->drive; if (loops++ < 4 && !blk_queue_plugged(drive->queue)) goto again; /* We clear busy, there should be no pending ATA command at this point. */ hwgroup->busy = 0; break; } hwgroup->rq = rq; /* * Some systems have trouble with IDE IRQs arriving while * the driver is still setting things up. So, here we disable * the IRQ used by this interface while the request is being started. * This may look bad at first, but pretty much the same thing * happens anyway when any interrupt comes in, IDE or otherwise * -- the kernel masks the IRQ while it is being handled. */ if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq) disable_irq_nosync(hwif->irq); spin_unlock(&ide_lock); local_irq_enable_in_hardirq(); /* allow other IRQs while we start this request */ startstop = start_request(drive, rq); spin_lock_irq(&ide_lock); if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq) enable_irq(hwif->irq); if (startstop == ide_stopped) hwgroup->busy = 0; } } /* * Passes the stuff to ide_do_request */ void do_ide_request(struct request_queue *q) { ide_drive_t *drive = q->queuedata; ide_do_request(HWGROUP(drive), IDE_NO_IRQ); } /* * un-busy the hwgroup etc, and clear any pending DMA status. we want to * retry the current request in pio mode instead of risking tossing it * all away */ static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error) { ide_hwif_t *hwif = HWIF(drive); struct request *rq; ide_startstop_t ret = ide_stopped; /* * end current dma transaction */ if (error < 0) { printk(KERN_WARNING "%s: DMA timeout error\n", drive->name); (void)HWIF(drive)->ide_dma_end(drive); ret = ide_error(drive, "dma timeout error", ide_read_status(drive)); } else { printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name); hwif->dma_timeout(drive); } /* * disable dma for now, but remember that we did so because of * a timeout -- we'll reenable after we finish this next request * (or rather the first chunk of it) in pio. */ drive->retry_pio++; drive->state = DMA_PIO_RETRY; ide_dma_off_quietly(drive); /* * un-busy drive etc (hwgroup->busy is cleared on return) and * make sure request is sane */ rq = HWGROUP(drive)->rq; if (!rq) goto out; HWGROUP(drive)->rq = NULL; rq->errors = 0; if (!rq->bio) goto out; rq->sector = rq->bio->bi_sector; rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9; rq->hard_cur_sectors = rq->current_nr_sectors; rq->buffer = bio_data(rq->bio); out: return ret; } /** * ide_timer_expiry - handle lack of an IDE interrupt * @data: timer callback magic (hwgroup) * * An IDE command has timed out before the expected drive return * occurred. At this point we attempt to clean up the current * mess. If the current handler includes an expiry handler then * we invoke the expiry handler, and providing it is happy the * work is done. If that fails we apply generic recovery rules * invoking the handler and checking the drive DMA status. We * have an excessively incestuous relationship with the DMA * logic that wants cleaning up. */ void ide_timer_expiry (unsigned long data) { ide_hwgroup_t *hwgroup = (ide_hwgroup_t *) data; ide_handler_t *handler; ide_expiry_t *expiry; unsigned long flags; unsigned long wait = -1; spin_lock_irqsave(&ide_lock, flags); if (((handler = hwgroup->handler) == NULL) || (hwgroup->req_gen != hwgroup->req_gen_timer)) { /* * Either a marginal timeout occurred * (got the interrupt just as timer expired), * or we were "sleeping" to give other devices a chance. * Either way, we don't really want to complain about anything. */ if (hwgroup->sleeping) { hwgroup->sleeping = 0; hwgroup->busy = 0; } } else { ide_drive_t *drive = hwgroup->drive; if (!drive) { printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n"); hwgroup->handler = NULL; } else { ide_hwif_t *hwif; ide_startstop_t startstop = ide_stopped; if (!hwgroup->busy) { hwgroup->busy = 1; /* paranoia */ printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name); } if ((expiry = hwgroup->expiry) != NULL) { /* continue */ if ((wait = expiry(drive)) > 0) { /* reset timer */ hwgroup->timer.expires = jiffies + wait; hwgroup->req_gen_timer = hwgroup->req_gen; add_timer(&hwgroup->timer); spin_unlock_irqrestore(&ide_lock, flags); return; } } hwgroup->handler = NULL; /* * We need to simulate a real interrupt when invoking * the handler() function, which means we need to * globally mask the specific IRQ: */ spin_unlock(&ide_lock); hwif = HWIF(drive); /* disable_irq_nosync ?? */ disable_irq(hwif->irq); /* local CPU only, * as if we were handling an interrupt */ local_irq_disable(); if (hwgroup->polling) { startstop = handler(drive); } else if (drive_is_ready(drive)) { if (drive->waiting_for_dma) hwgroup->hwif->dma_lost_irq(drive); (void)ide_ack_intr(hwif); printk(KERN_WARNING "%s: lost interrupt\n", drive->name); startstop = handler(drive); } else { if (drive->waiting_for_dma) { startstop = ide_dma_timeout_retry(drive, wait); } else startstop = ide_error(drive, "irq timeout", ide_read_status(drive)); } drive->service_time = jiffies - drive->service_start; spin_lock_irq(&ide_lock); enable_irq(hwif->irq); if (startstop == ide_stopped) hwgroup->busy = 0; } } ide_do_request(hwgroup, IDE_NO_IRQ); spin_unlock_irqrestore(&ide_lock, flags); } /** * unexpected_intr - handle an unexpected IDE interrupt * @irq: interrupt line * @hwgroup: hwgroup being processed * * There's nothing really useful we can do with an unexpected interrupt, * other than reading the status register (to clear it), and logging it. * There should be no way that an irq can happen before we're ready for it, * so we needn't worry much about losing an "important" interrupt here. * * On laptops (and "green" PCs), an unexpected interrupt occurs whenever * the drive enters "idle", "standby", or "sleep" mode, so if the status * looks "good", we just ignore the interrupt completely. * * This routine assumes __cli() is in effect when called. * * If an unexpected interrupt happens on irq15 while we are handling irq14 * and if the two interfaces are "serialized" (CMD640), then it looks like * we could screw up by interfering with a new request being set up for * irq15. * * In reality, this is a non-issue. The new command is not sent unless * the drive is ready to accept one, in which case we know the drive is * not trying to interrupt us. And ide_set_handler() is always invoked * before completing the issuance of any new drive command, so we will not * be accidentally invoked as a result of any valid command completion * interrupt. * * Note that we must walk the entire hwgroup here. We know which hwif * is doing the current command, but we don't know which hwif burped * mysteriously. */ static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup) { u8 stat; ide_hwif_t *hwif = hwgroup->hwif; /* * handle the unexpected interrupt */ do { if (hwif->irq == irq) { stat = hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]); if (!OK_STAT(stat, READY_STAT, BAD_STAT)) { /* Try to not flood the console with msgs */ static unsigned long last_msgtime, count; ++count; if (time_after(jiffies, last_msgtime + HZ)) { last_msgtime = jiffies; printk(KERN_ERR "%s%s: unexpected interrupt, " "status=0x%02x, count=%ld\n", hwif->name, (hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count); } } } } while ((hwif = hwif->next) != hwgroup->hwif); } /** * ide_intr - default IDE interrupt handler * @irq: interrupt number * @dev_id: hwif group * @regs: unused weirdness from the kernel irq layer * * This is the default IRQ handler for the IDE layer. You should * not need to override it. If you do be aware it is subtle in * places * * hwgroup->hwif is the interface in the group currently performing * a command. hwgroup->drive is the drive and hwgroup->handler is * the IRQ handler to call. As we issue a command the handlers * step through multiple states, reassigning the handler to the * next step in the process. Unlike a smart SCSI controller IDE * expects the main processor to sequence the various transfer * stages. We also manage a poll timer to catch up with most * timeout situations. There are still a few where the handlers * don't ever decide to give up. * * The handler eventually returns ide_stopped to indicate the * request completed. At this point we issue the next request * on the hwgroup and the process begins again. */ irqreturn_t ide_intr (int irq, void *dev_id) { unsigned long flags; ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id; ide_hwif_t *hwif; ide_drive_t *drive; ide_handler_t *handler; ide_startstop_t startstop; spin_lock_irqsave(&ide_lock, flags); hwif = hwgroup->hwif; if (!ide_ack_intr(hwif)) { spin_unlock_irqrestore(&ide_lock, flags); return IRQ_NONE; } if ((handler = hwgroup->handler) == NULL || hwgroup->polling) { /* * Not expecting an interrupt from this drive. * That means this could be: * (1) an interrupt from another PCI device * sharing the same PCI INT# as us. * or (2) a drive just entered sleep or standby mode, * and is interrupting to let us know. * or (3) a spurious interrupt of unknown origin. * * For PCI, we cannot tell the difference, * so in that case we just ignore it and hope it goes away. * * FIXME: unexpected_intr should be hwif-> then we can * remove all the ifdef PCI crap */ #ifdef CONFIG_BLK_DEV_IDEPCI if (hwif->chipset != ide_pci) #endif /* CONFIG_BLK_DEV_IDEPCI */ { /* * Probably not a shared PCI interrupt, * so we can safely try to do something about it: */ unexpected_intr(irq, hwgroup); #ifdef CONFIG_BLK_DEV_IDEPCI } else { /* * Whack the status register, just in case * we have a leftover pending IRQ. */ (void) hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]); #endif /* CONFIG_BLK_DEV_IDEPCI */ } spin_unlock_irqrestore(&ide_lock, flags); return IRQ_NONE; } drive = hwgroup->drive; if (!drive) { /* * This should NEVER happen, and there isn't much * we could do about it here. * * [Note - this can occur if the drive is hot unplugged] */ spin_unlock_irqrestore(&ide_lock, flags); return IRQ_HANDLED; } if (!drive_is_ready(drive)) { /* * This happens regularly when we share a PCI IRQ with * another device. Unfortunately, it can also happen * with some buggy drives that trigger the IRQ before * their status register is up to date. Hopefully we have * enough advance overhead that the latter isn't a problem. */ spin_unlock_irqrestore(&ide_lock, flags); return IRQ_NONE; } if (!hwgroup->busy) { hwgroup->busy = 1; /* paranoia */ printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name); } hwgroup->handler = NULL; hwgroup->req_gen++; del_timer(&hwgroup->timer); spin_unlock(&ide_lock); /* Some controllers might set DMA INTR no matter DMA or PIO; * bmdma status might need to be cleared even for * PIO interrupts to prevent spurious/lost irq. */ if (hwif->ide_dma_clear_irq && !(drive->waiting_for_dma)) /* ide_dma_end() needs bmdma status for error checking. * So, skip clearing bmdma status here and leave it * to ide_dma_end() if this is dma interrupt. */ hwif->ide_dma_clear_irq(drive); if (drive->unmask) local_irq_enable_in_hardirq(); /* service this interrupt, may set handler for next interrupt */ startstop = handler(drive); spin_lock_irq(&ide_lock); /* * Note that handler() may have set things up for another * interrupt to occur soon, but it cannot happen until * we exit from this routine, because it will be the * same irq as is currently being serviced here, and Linux * won't allow another of the same (on any CPU) until we return. */ drive->service_time = jiffies - drive->service_start; if (startstop == ide_stopped) { if (hwgroup->handler == NULL) { /* paranoia */ hwgroup->busy = 0; ide_do_request(hwgroup, hwif->irq); } else { printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler " "on exit\n", drive->name); } } spin_unlock_irqrestore(&ide_lock, flags); return IRQ_HANDLED; } /** * ide_init_drive_cmd - initialize a drive command request * @rq: request object * * Initialize a request before we fill it in and send it down to * ide_do_drive_cmd. Commands must be set up by this function. Right * now it doesn't do a lot, but if that changes abusers will have a * nasty surprise. */ void ide_init_drive_cmd (struct request *rq) { memset(rq, 0, sizeof(*rq)); rq->ref_count = 1; } EXPORT_SYMBOL(ide_init_drive_cmd); /** * ide_do_drive_cmd - issue IDE special command * @drive: device to issue command * @rq: request to issue * @action: action for processing * * This function issues a special IDE device request * onto the request queue. * * If action is ide_wait, then the rq is queued at the end of the * request queue, and the function sleeps until it has been processed. * This is for use when invoked from an ioctl handler. * * If action is ide_preempt, then the rq is queued at the head of * the request queue, displacing the currently-being-processed * request and this function returns immediately without waiting * for the new rq to be completed. This is VERY DANGEROUS, and is * intended for careful use by the ATAPI tape/cdrom driver code. * * If action is ide_end, then the rq is queued at the end of the * request queue, and the function returns immediately without waiting * for the new rq to be completed. This is again intended for careful * use by the ATAPI tape/cdrom driver code. */ int ide_do_drive_cmd (ide_drive_t *drive, struct request *rq, ide_action_t action) { unsigned long flags; ide_hwgroup_t *hwgroup = HWGROUP(drive); DECLARE_COMPLETION_ONSTACK(wait); int where = ELEVATOR_INSERT_BACK, err; int must_wait = (action == ide_wait || action == ide_head_wait); rq->errors = 0; /* * we need to hold an extra reference to request for safe inspection * after completion */ if (must_wait) { rq->ref_count++; rq->end_io_data = &wait; rq->end_io = blk_end_sync_rq; } spin_lock_irqsave(&ide_lock, flags); if (action == ide_preempt) hwgroup->rq = NULL; if (action == ide_preempt || action == ide_head_wait) { where = ELEVATOR_INSERT_FRONT; rq->cmd_flags |= REQ_PREEMPT; } __elv_add_request(drive->queue, rq, where, 0); ide_do_request(hwgroup, IDE_NO_IRQ); spin_unlock_irqrestore(&ide_lock, flags); err = 0; if (must_wait) { wait_for_completion(&wait); if (rq->errors) err = -EIO; blk_put_request(rq); } return err; } EXPORT_SYMBOL(ide_do_drive_cmd); void ide_pktcmd_tf_load(ide_drive_t *drive, u32 tf_flags, u16 bcount, u8 dma) { ide_task_t task; memset(&task, 0, sizeof(task)); task.tf_flags = IDE_TFLAG_OUT_LBAH | IDE_TFLAG_OUT_LBAM | IDE_TFLAG_OUT_FEATURE | tf_flags; task.tf.feature = dma; /* Use PIO/DMA */ task.tf.lbam = bcount & 0xff; task.tf.lbah = (bcount >> 8) & 0xff; ide_tf_load(drive, &task); } EXPORT_SYMBOL_GPL(ide_pktcmd_tf_load);